1. Field of the Invention
The present invention relates to a plasma display panel (hereinafter abbreviated PDP), and more particularly, to a front substrate of a plasma display panel and fabricating method thereof.
2. Description of the Background Art
Lately, a next generation multimedia display device plays a great important role as a visual information transfer means according to development and popularization of information processing systems. Specifically, as CRT (cathode ray tube) is inappropriate for the recent target of providing a large-sized and planarized screen, many efforts are made to study and develop such a flat panel display as LCD (liquid crystal display), FED (field emission display), PDP, ELD (electroluminescent display), etc.
The PDP is a self-emission display device using plasma gas discharge, and has such various advantages as facilitation of size increment, excellent image quality, and fast video response speed. Moreover, the PDP as well as LCD is used as a wall-hanging display. A discharge cell of a three electrode AC surface discharge type PDP is explained by referring to FIG. 1 as follows.
FIG. 1 is a cross-sectional view of a discharge cell of a three electrode AC surface discharge type PDP according to a related art.
Referring to FIG. 1, a discharge cell of the PDP is formed by combining a front substrate 110 and a back substrate 120 and by injecting discharge gas between the front and back substrates 110 and 120.
The front substrate 110 consists of an upper glass substrate 100, a transparent electrode 101 and bus electrode 102 formed on the upper glass substrate 100, an upper dielectric layer 103 formed on the upper glass substrate 100 including the transparent and bus electrodes 101 and 102 formed thereon, and a protection layer 104 formed on the upper dielectric layer 103.
In this case, the upper dielectric layer 103 restricts plasma discharge current and accumulates wall charges on plasma discharge.
The back substrate 120 consists of a lower glass substrate 109, an address electrode 108 formed on the lower glass substrate 109, a lower dielectric layer 107 formed on the lower glass substrate 109 including the address electrode 108, a barrier rib 106 formed on the lower dielectric layer 107, and a phosphor 105 formed on the lower dielectric layer 107 and the barrier rib 106.
An operational principle of the related art PDP is explained as follows.
First of all, a discharge sustain voltage is applied to the transparent and bus electrodes 101 and 102 to accumulate electric charges on the upper dielectric layer 103, and a discharge starting voltage is applied to the address electrode 108 so that the discharge gas injected in the discharge cells of the PDP such as He, Ne, Xe, and the like is separated into electrons and ions to be in a plasma state.
The phosphor 105 is excited by UV-rays generated from the reunion of the electrons and ions to emit visible rays that represent characters or graphics. In doing so, the PDP uses Ne having a relatively heavy atomic weight as a major component of the discharge gas to prevent thermal deformation, which is caused by collision of accelerated gas ions, of the phosphor or dielectric layer.
Yet, the discharged Ne gas radiates an orange visible ray (585 nm), thereby degrading color purity and contrast of the PDP.
To overcome such a problem, a color filter layer or a black stripe layer is added to the upper substrate of the PDP.
FIG. 2 is a cross-sectional view of a front substrate of PDP according to a related art.
Referring to FIG. 2, a front substrate of PDP according to a related art consists of an upper glass substrate 100, a transparent electrode 101 and bus electrode 102 formed on the upper glass substrate 100, an upper dielectric layer 103 formed on the upper glass substrate 100 including the transparent and bus electrodes 101 and 102 formed thereon, a color filter layer 103A formed on the upper dielectric layer 103A, and a protection layer 104 formed on the color filter layer 103A. In this case, the color filter layer 103A enables to adjust optical transmittance and to prevent surface reflection by an external light.
The above-constructed PDP according to the related art controls the optical transmittance of a color filter by the color filter layer to enhance the color purity of the PDP and prevents the surface reflection by the external light to enhance the contrast of the PDP.
However, the related art PDP needs to form the color filter layer on the upper dielectric layer, whereby a fabricating method thereof becomes complicated.
Moreover, in the related art PDP, the optical transmittance of a blue visible ray B is lower than that of a red or green visible ray R or G, whereby a color temperature of the PDP is about 6,000K. In order to compensate for the low color temperature, an input signal corresponding to R, G, or B is adjusted, barrier ribs are formed asymmetrical, or optical transmittance or dye of the color filter layer is adjusted. Yet, by adopting such a compensation, brightness of the PDP is reduced despite the compensation for the color temperature.
On the other hand, the color filter layer can be replaced by the black stripe layer. Yet, an aperture plane of the black stripe layer is small, whereby emission efficiency of the PDP is reduced.
As mentioned in the foregoing explanation, the related art PDP needs to form the color filter layer on the upper dielectric layer, whereby the fabricating method thereof becomes complicated.
Moreover, the optical transmittance of the blue visible ray B is lower than that of the red or green visible ray R or G, whereby the color temperature of the PDP is low.